Texas-based Williams Fire & Hazard Control's usual forte is extinguishing flammable liquid fires in storage tanks measuring hundreds of feet in diameter. But the intense, stubborn fires after a devastating explosion at a sugar refinery in Port Wentworth, GA., presented a different kind of challenge.
Savannah area responders handled the structural fire fighting after the February 7 blast that wrecked nearly 20 percent of the sprawling refinery and eventually claimed 13 lives. However, high temperature fires inside two 40-foot (12 meter)-wide, 100-foot (30.4 meter)-tall sugar silos defied local efforts, including massive water drops from a helicopter.
Williams F&HC's proven track record extinguishing silo fires involves contents ranging from coal to shredded tires. The Port Wentworth incident gave the company a chance to prove its technique against a powdery target that normally does not qualify as volatile.
Company spokesman Brent Gaspard said an attendee at last year's XTREME Industrial Fire & Hazard Training School contacted Williams F&HC lead firefighter Chauncey Naylor about tackling the persistent silo fires that burned five days.
"This fellow asked Chauncey if Williams F&HC had ever put out a sugar fire," Gaspard said. "Chauncey said no. When asked if we had ever put out a silo fire. Chauncey said yes. Basically, that's how we got the job."
Naylor and the Williams F&HC team arrived in Port Wentworth on the afternoon of Feb. 12. Of the three sugar silos surrounded by the collapsed structure of what had been the refinery's packaging area, two had the tops blown off and were burning at nearly 4,000 degrees F (2,200 degrees C) inside.
Concerns about further collapses, including the impact of continuous water drops on the silos, made a ground operation impossible.
"Chauncey determined that an over-the-top application was the way to go," Gaspard said. "Our guys did a lot of their work from a basket lifted by a crane."
Bringing adequate water to the fire proved to be the first challenge. Naylor brought in a new Williams F&HC product, a 4,000 gpm (15,000 lpm) submersible pump called The NHancer. Because the on site fire water tank was depleted, the firefighters were forced to draft from the nearby Savannah River.
"Even though the pump was a couple of thousand feet away we were able to supply the entire fire water response needs from the river," Gaspard said. "The NHancer sat in the river and brought the water to two supply pumps. The supply pumps were used in relay to increase and maintain pressure for fire response. We laid down Double 5 large 7?-diameter fire hose to initiate the response."
Firefighters were able to maintain a pressure of 150 psi (10 B) before elevation, he said. The NHhancer was lowered from a crane and its depth constantly monitored by the crane operator.
"There is a six-to-eight foot (1.8 to 2.5 meter) differential in the tides of that river, so what he did is basically elevate and lower that pump with the rising and lowering of the water," Gaspard said.
Working closely with local contractor Savannah Bridge and Crane, Williams F&HC fabricated standpipes next to the collapsed building.
"That allowed us to get the large diameter hose up and over debris adjacent to the silos, working the hose up the adjacent stairwell tower," Gaspard said.
With the first burning silo, firefighters took a standard Williams F&HC 95 gpm (360 L) Foam Wand, an unmanned device designed to expand and deliver foam into remote, hazardous areas, and fabricated an extension with an Elkhart distributor nozzle on the end. Normally, the Foam Wand hangs over the rim of a burning tank. In this case it was lowered deep into the burning silo. An application rate of 0.5 percent was used.
"It was very effective," Gaspard said.
In tribute to the contribution made by local firefighters, Port Wentworth Fire Chief Greg Long was given the honor of opening the valves that initiated the silo fire response.
Operations moved to the next burning silo immediately adjacent to the refinery's stairwell tower. Williams F&HC personnel fabricated special brackets that allowed firefighters to secure two mini-Daspit monitors to the tower as well as a full-sized Daspit to apply water and foam applications into the silos from above. Full sized Daspits are usually secured to the rim of large diameter storage tanks to deal with rim fires and vapor suppression.
"The Daspit shooting down into that second burning silo was elevated almost 100 feet (30.4 meters) off the ground," Gaspard said. "At that elevation you're going to lose some pressure. Yet we were maintaining more than 100 psi (45 K), enough to maintain multiple attacks."
When tackling crude oil fires, Williams F&HC firefighters employ a technique known as "the tease." That technique came into play at Port Wentworth.
"The top layer of crude, possibly as deep as three or four feet, will be above the boiling point of water somewhere between 400 and 500 degrees F (200 to 260 degrees C)," Williams F&HC CFO/chairman Dwight Williams once explained. "If the monitor stream hits the hot crude all at once it would jump right out of the tank."
The solution is to work the stream back and forth across the surface, slowly bringing the temperature down.
"That's what we did in Port Wentworth because the structure of those silos used concrete," Gaspard said. "Chauncey didn't want any vapor expansion going on inside, blowing those walls apart."
Local firefighters employing water drops were only able to bring the temperature in the silos down from 4,000 degrees F (2,200 degrees C) to 2,800 degrees F (1,500 degrees C). At the end of the Williams F&HC operation, the temperature in the silos was only 62 degrees F (16 degrees C).
In total, Williams F&HC spent one afternoon for site assessment and equipment requisition, one day for set up and complete extinguishment and a final day for break down and return home.
Williams F&HC was even able to help local firefighters deal with the last of the lingering structural fires.
"The municipal responders were dealing with a lot of little ground fires because of all the paper used in packaging the sugar," Gaspard said. "They were having to go back and put these fires out a second or third time."
Williams F&HC provided foam for the municipal foam truck using the pump system. The results were immediate.
"Getting foam into their response methods made a big difference," Gaspard said. "Their mission was finished."
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